Head teachers are set to join an unprecedented wave of strikes that will bring
almost every school in England and Wales to a standstill.

The National Association of Head Teachers is expected to back proposals for a national walk out to defend members’ pensions.

An emergency motion to be debated at the union’s annual conference in Brighton on Sunday will call on the union to take any action necessary – up to and including strikes – to block controversial changes to teachers’ retirement funds.

The move comes just days after two major teaching unions announced they would ballot members for a one-day strike in the summer term, followed by a series of walk-outs in September and October.

The National Union of Teachers and the Association of Teachers and Lecturers backed the proposed action earlier this month.

It raises the prospect of co-ordinated strike action that would shut the majority of state primary and secondary schools in England and Wales, possibly in late June. Hundreds of independent schools are also likely to shut

The action would cause chaos for millions of parents who will be forced to hire childminders or take a day off work to look after sons and daughters who have been locked out of school.

It promises to be the first national teachers’ strike since 2008 and only the second in 24 years.

Russell Hobby, general secretary of the NAHT, which represents 28,000 heads and deputies, said: “What’s being proposed is effectively a pay cut, which is something our members feel is particularly offensive at a time when they are being expected to work even longer hours and take on more responsibilities because of Government cuts. Heads have an appetite for a fight on this one.”

An independent review of public sector pensions by Lord Hutton last month proposed that nurses, teachers and most other public sector staff should work until at 65 for lower pensions. They should also be linked to career average earnings rather than final salaries, he suggested.

Changes are needed as the price of pensions is no longer sustainable because of the national debt and rising life expectancy, the Coalition claim.

But the conclusions have outraged unions who claim staff could desert the teaching profession over the changes.

Under plans, the NUT are set to ballot up to 300,000 members in schools in England and Wales, while the ATL is likely to ballot 80,000.

They want to ballot for “discontinuous” action – giving them permission to stage a series of one-day strikes.

The ballots will take place if current negotiations between the Government and the Trades Union Congress fail to reach an acceptable outcome, unions say.

Mr Hobby suggested that the NAHT could join June strikes, although it is more likely that the union could not take industrial action until September at the earliest.